US2321039A - Protective armor - Google Patents

Description

2 Sheets-Sheet l B. C. NELSON PROTECTIVE ARMOR Filed Nov, 2l, 1959 Jun@ H9433.,

June 8, 1943. B. c. NELSON 2,321,039

PROTECTIVE ARMOR Filed Nov. 21, 1939 2 Sheets-Sheet 2 'IIV Patented June S, 1943 UNITED STATS ii'i'ENT OFFICE PROTECTIVE ARMOR Buell C. Nelson, Portland, Greg.

Application November 21, 1939, Serial No. 305,467

6 Claims.

My invention relates to armor for protecting battleships or other objects from the projectiles of large guns, torpedoes, bombs, and the like, and it relates more particularly to armor plate of the type adapted to yield a substantial amount under impact, rather than to maintain its rigidity thereunder.

It is well known that a large projectile can be stopped by a relatively light force provided said force acts through a substantial distance; the kinetic energy of the projectile will be numerically edual to the product of said force and said distance.

The principal object of my invention is to provide metallic armor that will be yieldable to absorb gradually the kinetic energy of a projectile or the explosive force of a shell, bomb, torpedo, or the like. I achieve said object by constructing a cellular armor comprising a number of layers of cells through which a missile would have to pass to reach the interior of the boat or other object to be protected. I also place, preferably in each of said cells, a movable plate adapted to act as a piston to compress air therein, a part of the energy of the projectile being transferred thereby to said air, whereas said energy has been absorbed wholly by the metal in armor heretofore used.

A further object of my invention is to provide yieldable armor that will be equally effective at all points on its surface. A considerable difliculty in providing armor embodying movable plates adapted to function as pistons arises from the .fact that, when said plates are struck at any point other than their middle, they tend to rotate as well as to move forward bodily. It follows that a projectile striking a plate near its edge will meet with less resistance than it would if it struck at the middle of the plate. I provide an armor that is .substantially free from vulnerable spots by the arrangement of plates hereinafter described.

A further object of my invention is to provide armor for boats, tanks, and the like, and also for nverhead protection of various objects, that is light in weight and economical of material considering the strength of the impact it is adapted to withstand.

Other objects and advantages of my invention will be described with reference to the accompanying drawings, in which:

Fig. l is a side View of a battleship embodying my invention, a portion of the outer skin thereof being shown broken away;

Fig. 2 is a vertical fragmentary sectional view of the armor of said battleship, being taken on the line 2-2 in Fig. 3;

Fig. 3 is a vertical section taken on the line 3 3 in Fig. 2;

Fig. 4 is a diagrammatical perspective view (Cl. 89u36) showing the arrangement of movable plates which I prefer;

Fig. 5 is a view similar to Fig. 2, a projectile being shown as it would appear when rst striking the armor;

Fig. 6 is a view similar to Fig. 5, said projectile being shown after partially penetrating said armor;

Fig. 7 is a view similar to Fig. 6, said projectile being shown after further penetrating said armor;

Fig. 8 is a View similar to Fig. 7, said projectile being shown after it has been stopped by said armor; and

Fig. 9 is a diagrammatic view illustrating manner of application of a force to two overlapped plates. Y

Cellular armor embodying my invention comprises a rather thick inner plate i which may be considered to be the ordinary armor plate of battleship 2 except that it is much thinner than said armor plate would have to be were it not for said cellular structure. Outside plate I, spaced therefrom and supported by lateral members, or partitions, 3 is a thinner plate 4. Said Partitions may be welded to said plates, if desired. Between plates I and 4, bounded by partitions 3, are thus formed cells 5 which I prefer to be completely closed on all sides, being water tight. If desired, said cells might also be made air tight, and they might then be filled with air at a pressure higher than atmospheric, although atmospheric pressure will ordinarily be sulicient.

Within said cells, and preferably filling substantially all of the area between partitions 3, are what I call movable plates 6. However, said movable plates may, if desired, be fastened to the outer stationary plate of its cell by straps 1, said straps being welded to said movable plates and to said stationary plates. Said movable plates will thus be held securely enough so that they will not move under vibration forces, and the like, but they will not be held so firmly as to interfere with their functioning as pistons when struck by a J projectile.

The outer wall 8 of the outermost of cells 5 may be made somewhat thicker than stationary plates 4.

The way in which movable plates 6 function to cushion and gradually absorb the kinetic energy of a projectile is illustrated in said Figs. 5 to 8. It will be understood that said figures are merely intended to illustrate the principle whereby said movable plates are carried along by said projectile, compressing the air in cells 5 momentarily, to reduce the velocity of the projectile. No attempt is made therein to portray accurately the kind of hole formed in the stationary plates, or to illustrate the denting of the movable plates that 60 will occur when the projectile rst strikes them.

When a projectile rst strikes a movable plate it will be opposed mainly by the inertia of said plate resisting displacement thereof. Said plate should be so designed that it will not be pierced by said projectile, and this result will be achieved most readily if said movable plate is made of some tough alloy steel, such as manganese steel. After said movable plate has moved a short distance, the travel of said projectile will 'be opposed largely by the compression of the air ahead of said plate; that is, the initial inertia force will gradually decrease, while the force due to the compression of the air will increase as the plate moves from the outer side of the cell to the inner side thereof.

Inasmuch as a projectile striking near the edge of a movable plate will be opposed by less force, either due to the inertia of the plate or to the compression of air thereby, than if it struck the middle of the plate, it will be apparent that armor constructed of a single layer of cells or several unstaggered layers, and movable plates would be subject to the objection that, although some portions thereof might aiord adequate protection, other parts would be vulnerable unless a construction so heavy as to defeat, to a large extent, the purpose of the invention were adopted. The protection would not be wholly reliable, but would depend largely on the point at which the projectile chanced to strike.

This difficulty is due primarily to the tendency of a plate to rotate when struck, that is, the plate will tip if struck near its edge instead of acting as a piston. However, if another plate, either in front of or behind it, is horizontally offset therefrom by half its width, the total cushioning effect of the two plates will be the same at al1 points along a horizontal line on their surface. This is illustrated in Fig. 9 wherein two plates I IJ and, II overlap an amount equal to one-half their length L. It will be understood that said plates represent particular ones of plates 6, being arranged in cells to act as pistons, plate II being behind plate ID a substantial distance. If a projectile strikes plate lil at point P at a distance :i: to the right of the center line of said plate, the torque tending to rotate said plate about said center line will be where F is the force exerted by the projectile on said plate. On the other hand, when said projectile strikes plate I I, it will produce a torque Assuming that F is equal to F', thus ignoring the slowing down of the projectile as it passes through plate I0, the sum of these two torques is In the above equations, t1 is the torque exerted upon plate Ill (Fig. 9), t2 is the torque exerted upon plate II, `F is the force exerted by the projectile on plate IB, F is the force exerted by the projectile on plate II, :r is the distance from the center of plate I to the po-int where the projectile strikes, and L is the length of plates I0 and II. Thus the rotative torque exerted by the projectile on the two plates is independent of at; that is, it doesnt matter where the projectile strikes.

As'mentioned, the foregoing equation is based on the assumption that the projectile exerts the same force on the first plate it strikes as on the succeeding plates. Subject to this qualification, the use of two layers of plates matching each other vertically, but staggered from right to left results in a structure that will uniformly oppose the passage of a projectile therethrough regardless of the point at which said projectile strikes along a horizontal line. It will not, however, offer uniform opposition to said projectile if the latter strikes at different points vertically. I desire that said uniformity of opposition shall apply to all points on the surface of the armor, that is, I desire to provide armor plate that will have no vulnerable spots. I therefore provide four layers of plates to achieve as to all directions the result hereinbefore discussed, with reference to Fig. 9, as to one direction.

Referring to Fig. 4, which is a perspective view of four layers of plates spaced a substantial distance from each other, the rearmost layer of plates I2 may conveniently be taken as a reference basis with which to describe the positions of the other layers of plates. Fig. 9 illustrates plates staggered horizontally with respect to each other. Fig. 4 shows plates staggered horizontally and, in addition, another layer staggered vertically, and another staggered both horizontally and vertically. Specifically, layer I3 is staggered both horizontally and vertically with respect to layer I2. Layer I is staggered only horizontally with respect to layer I2, and layer I5 is staggered only vertically with respect to layer I2.

The structure illustrated in Fig. 4 functions according to the principle discussed in connection with Fig. 9. Layers I2 and I4 a-re staggered from left to right and consequently offer, together, uniform opposition to a projectile striking anywhere along a horizontal line. Similarly, layers I2 and I5 are staggered vertically and, consequently, they, together, offer uniform opposition to a projectile striking anywhere along a vertical line. The combination of layers I2, Id, and I5, wherein the plates are out of registration, then, would offer uniform opposition to a projectile striking anywhere along either a horizontal line or a vertical line, but the opposition would be different for different horizontal and vertical lines, being least at the corners of the plates. The addition of layer I3, staggered both horizontally and vertically, results in structure that will oifer uniform opposition to a projectile regardless of where it strikes, except for the qualication hereinbefore referred to regarding the different force of the projectile against different layers.

As a practical matter, a projectile striking near the edge of one of the outer plates of Fig. 4 will be opposed by the aggregate of plates only a little less effectively then if it strikes near the center of said plates. If said outer plates were made progressively a little thinner than the inner ones, this difference would be further minimized- It will be apparent that the order in which the layers of Fig. 4 are placed is a matter of indifference. For example, layer I4 might be staggered vertically with respect to layer I2, and layer I5 might be staggered horizontally without changing the result in any way.

Thus I have described a multi-layer cellular armor having pistons within the cells to compress air therein, thus cushioning the projectile and gradually stopping it. I have also described an arrangement of said cells wherein the movable plates are staggered in such a way that said cushioning effect will be substantially uniform regardless of where the projectile strikes. The resultant armor offers better protection with less weight and cost than that heretofore used, perhaps requiring a little more space, however, than solid armor.

I deem said structure to be useful wherever an object is to be protected from missiles of any' kind. However, an advantage of said structure peculiar to its application to the hulls of boats is due to its tendency to absorb, rather than to transmit, shocks. With armor heretofore used on boats, a torpedo striking, say, near the bow might rupture a few water-tight compartments without endangering the boat. However, due to the rigidity of said armor, the shock of the explosion of said torpedo might be transmitted to other parts of the boat and there cause leakage of other compartments that would ultimately result in the sinking of the boat. It will be apparent that due to its cellular nature, the armor herein described will not transmit shocks as well as the thicker armor that would otherwise be necessary. I, therefore, deem my invention to be of particular value for use on the hulls of boats.

I claim:

l. Protective armor comprising a plurality of connected layer members in spaced apart relation, certain of said layers being formed of a series of contiguous elements, supported adjacent their margins by easily rupturable elements, transverse members lying intermediate the several layers and joining said layers one with the other, said transverse members lying closely about the margins of the layer members, respectively, whereby said layer members are adapted to be broken loose from their points of joinder by a low and moved bodily into said structure, closely encompassed by said transverse members.

2. Protective armor comprising a plurality of connected layer members in spaced apart relation, certain of said layers being formed of a series of contiguous elements, supported adjacent their margins by easily rupturable elements,

transverse members lying intermediate the several layers and joining said layers one with the other, said transverse members lying closely about the margins of the layer members respectively, said elements being relatively stiff and adapted to remain unpierced by a blow suflicient to break the marginal joinder to the remainder of a layer, whereby said layer members are adapted to be broken loose from their points of joinder by a blow and moved bodily into said structure, closely encompassed by said transverse i members.

3. In a ship, a wall structure comprising five structurally united layers of plates spacedv apart one layer from the other to form four spaces, and

late

iiovement in each of said spaces, easily broken securing means holding said plate members in said spaces, movement of said plate members, after said securing means have been broken, being restricted only by air resistance and inertia of said plate members, said suspended plate members being arranged in said wall structure so that their centers are offset with respect to the centers of overlying and underlying suspended plate members a distance substantially one-half the length of each of said suspended plate members.

4. In a ship, a wall structure comprising a plumembers of uniform size suspended for L the rality of structurally united layer members, said layer members being spaced apart a substantial distance, imperforate lateral members extending across the space between said layer members and dening a course made up of a plurality of cells therein, a plate member of substantially lesser thickness than the space between said layer members suspended for movement in each of said cells adjacent one of said layer members, said lateral members closely encompassing the periphery of the plate member in each cell, and easily rupturable securing means for holding each plate member suspended in its cell, each plate member being relatively stii and adapted to remain undistorted by a force sufficient to rupture the securing means and to shift said plate member laterally of its encompassing cell, movement after said securing means has been ruptured being restricted solely by air resistance and the inertia of said plate member.

5. In a ship, a wall structure made up of a plurality of super-imposed courses, each course comprising a plurality of structurally united layer members, said layer members being spaced apart a substantial distance, imperforate lateral members extending across the space between said layer members and defining a plurality of cells therein, a plate member of substantially lesser thickness than the space between said layer members suspended for movement in each of said cells adjacent one of said layer members, said lateral members closely encompassing the periphery of the plate member in each cell, and easily rupturable securing means for holding each plate member suspended in its cell, each plate member being relatively stiff and adapted to remain undistorted by a force sufficient to rupture the securing means and to shift said plate member laterally of its encompassing cell, movement after said securing means has been ruptured being restricted solely by air resistance and the inertia of said plate member, the cells and the plate members therein being arranged in said wall structure in the plurality of courses with the cells therein offset from those in adjacent courses.

6. In a ship, a wall structure made up of a plurality of super-imposed courses, each course comprising a plurality of structurally united layer members, said layer members being spaced apart a substantial distance, imperforate lateral members extending across the space between said layer members and dening a plurality of cells therein, a plate member of substantially lesser thickness than the space between said layer members suspended for movement in each of said cells adjacent one of said layer members, said lateral members closely encompassing the periphery 0f the plate member in each cell, and easily rupturable securing means for holding each plate member suspended in its cell, each plate member being relatively stiff and adapted to remain undistorted by a force sufficient to rupture the securing means and to shift said plate member laterally of its encompassing cell, movement after said securing means has been ruptured being restricted solely by air resistance and the inertia of said plate member, the cells and the plate members therein being arranged in said Wall structure in the plurality of courses with the cells therein oiTset from those in adjacent courses, said cells being offset a distance substantially one-half the length and width, respectively, of said plate members.

BUELL C. NELSON.

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